A system for validating biosensor data, the system comprising: i) means for collecting biosensor data from a subject; ii) means for reproducing subject behaviour and/or physiological activity of the subject and collecting data corresponding with such reproduced behaviour and/or physiological activity; and iii) means for detecting any deviation over time in biosensor data collected from the reproduced activity in (ii) in order to identify and/or correct sensor or software introduced deviations in biosensor data collected from the patient.